Tetrahydrophthalimides, and their production and use

ABSTRACT

A compound of the formula: ##STR1## wherein X is a chlorine atom or a bromine atom, which is useful as a herbicide.

The present invention relates to N-(2-fluoro-4-halo-5-substitutedphenyl)-3,4,5,6-tetrahydrophthalimide derivatives (hereinafter referredto as "tetrahydrophthalimide(s)"), and their production and use.

The said tetrahydrophthalimides are representable by the formula:##STR2## wherein X is a chlorine atom or a bromine atom.

It is known that certain kinds of N-phenyltetrahydrophthalimides areeffective as herbicides. For instance, the herbicidal use of2-fluoro-4-chlorophenyltetrahydrophthalimide,2,4-dichloro-5-isopropoxyphenyltetrahydrophthalimide, etc. is disclosedin U.S. Pat. No. 4,032,326, U.K. Patent Publication No. 2046754A, etc.However, their herbicidal effect is still not always satisfactory.

It has now been found that the tetrahydrophthalimides (I) show a strongherbicidal activity against a wide variety of weeds including Gramineaeweeds, Cyperaceae weeds and broad-leaved weeds at small doses and do notproduce any material phytotoxicity on various agricultural crops.Examples of Gramineae weeds against which the tetrahydrophthalimides (I)show a herbicidal activity are barnyardgrass (Echinochloa crus-galli),green foxtail (Setaria viridis), large crabgrass (Digitariasanguinalis), Johnsongrass (Sorghum halepense), wild oat (Avena fatua),water foxtail (Alopecurus geniculatus), goosegrass (Eleusine indica),annual bluegrass (Poa annua), bermudagrass (Cynodon dactylon),quackgrass (Agropyron repens), etc. Examples of Cyperacaea weeds arenutsedge sp. (Cyperus sp.), purple nutsedge (Cyperus rotundus), hardstembulrush (Scirpus juncoides), nutsedge (Cyperus serotinus), waterchestnut (Eleocharis kuroguwai), slender spikerush (Eleocharisacicularis), etc. Examples of broad-leaved weeds are tall morningglory(Ipomoea purpurea), velvetleaf (Abutilon theophrasti), sicklepod (Cassiaobtusifolia), wild sunflower (Helianthus annus), cocklebur (Xanthiumpennsylvanicum), wild mustard (Brassica kaber), common chickweed(Stellaria media), common pursland (Portulaca oleracea), jimsonweed(Datura stramonium), hemp-sesbania (Sesbania exaltata), sun spurge(Euphorbia helioscopia), prickly sida (Sida spinosa), common ragweed(Ambrosia artemisifolia), smartweed sp. (Polygonum sp.), redroot pigweed(Amaranthus retroflexus), bedstraw (Galium aparine), pineappleweed(Matricaria spp.), birdseye speedwell (Veronica persica), wild buckwheat(Polygonum convolvulus), ladysthumb ( Polygonum persicaria), beggarticks(Bidens spp.) common lambsquarters (Chenopodium album), black nightshade(Solanum nigrum), bindweed (Calystegia japonica), monochoria (Monochoriavaginalis), American waterwort (Elatine americana), false pimpernel(Lindernia procumbens), toothcup (Rotala indica), arrowhead (Sagittariapygmaea), etc.

Accordingly, the tetrahydrophthalimides (I) can be used as herbicidesapplicable for field crops and vegetables as well as paddy rice. Theyare also useful as herbicides to be employed for orchard, lawn, pasture,tea garden, mulberry field, rubber plantation, forest, etc. applications

The tetrahydrophthalimides (I) can be produced by various procedures,among which typical examples are shown below.

Procedure A

The tetrahydrophthalimide (I) is obtainable by reacting an aniline ofthe formula: ##STR3## wherein X is as defined above with3,4,5,6-tetrahydrophthalic anhydride, in the absence or presence of aninert solvent (e.g. benzene, toluene, xylene, 1,4-dioxane, acetic acid,propionic acid) while heating. The reaction is normally accomplished ata temperature of 70° to 200° C. for a period of 0.5 to 5 hours. Themolar ratio of the aniline (II) and the tetrahydrophthalic anhydride ispreferred to be from 1:1.0 to 1:1.1.

Procedure B

The tetrahydrophthalimide (I) is obtainable by reacting ahydroxyphenyltetrahydrophthalimide of the formula: ##STR4## wherein X isas defined above with an isopropyl halide (e.g. isopropyl chloride,isopropyl bromide, isopropyl iodide), usually in an inert solvent (e.g.dimethylformamide, dimethyl sulfoxide) in the presence of a base such asan alkali metal carbonate (e.g. potassium carbonate), an alkali metalhydroxide (e.g. potassium hydroxide), an alkali metal hydride (e.g.sodium hydride) or an alkali metal alkoxide (e.g. sodium methoxide,sodium ethoxide). The most preferred base is an alkali metal carbonate.The reaction temperature is normally from 0° to 100° C., preferably from40° to 90° C. The molar ratio of the hydroxyphenyltetrahydrophthalimide(III) and the halide is preferred to be from 1:1.0 to 1:1.1.

The thus produced tetrahydrophthalimide (I) may be, when desired,purified by a per se conventional procedure such as recrystallization orcolumn chromatography.

The aniline (II) as the starting material in Procedure A and thehydroxyphenyltetrahydrophthalimide (III) as the starting material inProcedure B can be produced from a phenol of the formula: ##STR5##wherein X is as defined above according to the following scheme:##STR6## wherein X is as defined above.

Namely, the aniline (II) may be produced from the phenol (IV) bynitrating the same, subjecting the resultant nitrophenol (V) toalkylation, and reducing the resulting alkoxy-nitrobenzene (VI). Thehydroxyphenyltetrahydrophthalimide (III) can be manufactured from thephenol (IV) by nitrating the same, reducing the resultant nitrophenol(V) and reacting the resulting aminophenol (VII) with3,4,5,6-tetrahydrophthalic anhydride.

Conversion of the phenol (IV) into the nitrophenol (V) may beaccomplished by application of a per se conventional nitration procedureto the former. Usually, however, the indirect nitration which consistsof the following three steps is favorable in achievement of theselective nitration at the desired position: ##STR7## wherein X is asdefined above. Thus, the phenol (IV) is converted into its alkali metalsalt by treatment with an aqueous solution of an alkali metal hydroxide(e.g. sodium hydroxide, potassium hydroxide), and the resulting salt isreacted with an alkyl haloformate such as methyl chloroformate in waterat a temperature of 0° to 10° C. The thus prepared carbonic ester (VIII)is nitrated with a mixture of conc. sulfuric acid and conc. nitric acidat room temperature. Then, the nitrobenzene (IX) thus obtained ishydrolyzed with an aqueous alkaline solution such as an aqueous sodiumhydroxide solution at a temperature of 20° to 120° C. to give thenitrophenol (V).

The alkylation for conversion of the nitrophenol (V) into thealkoxy-nitrobenzene (VI) may be carried out by treatment of the formerwith an alkali metal carbonate (e.g. potassium carbonate), an alkalimetal hydride (e.g. sodium hydride) or an alkali metal alkoxide (e.g.sodium methoxide) and reacting the resultant alkali metal salt with anisopropyl halide in a polar solvent (e.g. water, dimethylformamide,acetonitrile, acetone, dimethylsulfoxide), usually at a temperature of10° to 200° C., preferably of 30° to 100° C. The use of a phase transfercatalyst such as tetrabutylammonium bromide is favorable for smoothaccomplishment of the reaction.

Reduction of the alkoxy-nitrobenzene (VI) to the aniline (II) may beachieved by various procedures. For instance, there may be adopted a perse conventional reduction procedure for converting a nitro group into anamino group wherein a reducing agent such as sodium sulfide or ironpowder or catalytic reduction is employed. One of the typical procedurescomprises introduction of a 3 molar amount of hydrogen into a reactionsystem comprising one molar amount of the compound (VI) and a 1/10 to1/100 molar amount of platinum dioxide at room temperature underatmospheric pressure. Another typical procedure comprises admixing anacetic acid solution containing one molar amount of the compound (VI)with a 5% acetic acid solution containing a 2 to 5 molar amount of ironpowder such as reductive iron or electrolytic iron and effecting thereaction at a temperature of 80° to 100° C.

Conversion of the nitrophenol (V) into the aminophenol (VII) may beaccomplished by any per se conventional reduction procedure for changinga nitro group to an amino group. Examples of such reduction procedureare catalytic reduction, reduction with iron powder, reduction withsodium sulfide, reduction with sulfurated sodium borohydride, etc. Forinstance, treatment of one molar amount of the nitrophenol (V) with a 3molar amount of hydrogen in the presence of a 1/10 to 1/100 molar amountof platinum dioxide in an inert solvent (e.g. ethanol, ethyl acetate) atroom temperature under atmospheric pressure affords the aminophenol(VII). Further, for instance, treatment of one molar amount of thenitrophenol (V) with a 2 to 5 molar amount of iron powder such asreductive iron or electrolytic iron in a 5% acetic acid solution or adilute hydrochloric acid solution at a temperature of 80° to 100° C. fora period of 1 to 5 hours produces the aminophenol (VII).

For production of the hydroxyphenyltetrahydrophthalimide (III) from theaminophenol (VII), the latter is reacted with 3,4,5,6-tetrahydrophthalicanhydride in an inert solvent (e.g. acetic acid) while refluxing for aperiod of 1 to 6 hours, preferably of 2 to 4 hours.

Still, the phenol (IV) is known (cf. Finger et al.: J.Am.Chem.Soc., 81,94 (1959)).

Practical and presently preferred embodiments of the production of theobjective tetrahydrophthalimide (I) as well as the intermediarycompounds including those of the formulas: ##STR8## wherein R is ahydrogen atom or an isopropyl group and X is as defined above areillustratively shown below:

EXAMPLE 1

Production of the tetrahydrophthalimide (I: X=Cl; R=iso--C₃ H₇):

4-Chloro-2-fluoro-5-isopropoxyaniline (1.3 g) and3,4,5,6-tetrahydrophthalic anhydride (1.12 g) were dissolved in aceticacid (10 ml) and refluxed for 3 hours. The resultant mixture was allowedto cool to room temperature and poured into water, followed byextraction with ether. The ether extract was washed with water, driedover anhydrous sodium sulfate and subjected to filtration. The filtratewas concentrated under reduced pressure and the residue was purified bysilica gel chromatography to obtain 1.0 g ofN-(4-chloro-2-fluoro-5-isopropoxyphenyl)-3,4,5,6-tetrahydrophthalimide(Compound No. 1). M.P., 81°-82° C.

NMR (CCl₄) δ(ppm): 1.35 (6H, d, J=6 Hz), 1.75 (4H, m), 2.3 (4H, m), 4.4(1H, q, J=6 Hz), 6.65 (1H, d, J=6 Hz), 7.1 (1H, d, J=10 Hz).

EXAMPLE 2

Production of the tetrahydrophthalimide (I: X=Cl; R=iso--C₃ H₇):

To a solution ofN-(4-chloro-2-fluoro-5-hydroxyphenyl)-3,4,5,6-tetrahydrophthalimide(2.95 g) in dimethylformamide (20 ml), there was added anhydrouspotassium carbonate (0.8 g) while stirring at room temperature. Afterstirring for 10 minutes at about 40° C., isopropyl iodide (1.7 g) wasadded thereto, and the resultant mixture was stirred for 3 hours at70°-80° C. After being allowed to cool to room temperature, the mixturewas poured into water and extracted with toluene. The toluene layer waswashed with water, dried over anhydrous sodium sulfate and concentrated.The residue was purified by silica gel chromatography to obtain 1.2 g ofN-(4-chloro-2-fluoro-5-isopropoxyphenyl)3,4,5,6-tetrahydrophthalimide(Compound No. 1). M.P., 81°-82° C.

EXAMPLE 3

Production of the tetrahydrophthalimide (I: X=Br; R=iso--C₃ H₇):

4-Bromo-2-fluoro-5-isopropoxyaniline (2.0 g) and3,4,5,6-tetrahydrophthalic anhydride (1.23 g) were dissolved in aceticacid (10 ml) and refluxed for 3 hours. The resultant mixture was allowedto cool to room temperature and poured into water, followed byextraction with ether. The ether extract was washed with water, driedover anhydrous sodium sulfate and subjected to filtration. The filtratewas concentrated under reduded pressure, and the residue was purified bysilica gel chromatography to obtain 1.6 g ofN-(4-bromo-2-fluoro-5-isopropoxyphenyl)-3,4,5,6-tetrahydrophthalimide(Compound No. 2). M.P., 116.5°-117.5° C.

NMR (CDCl₃) δ(ppm): 1.35 (6H, d, J=6 Hz), 1.75 (4H, m), 2.3 (4H, m), 4.4(1H, q, J=6 Hz), 6.75 (1H, d, J=6 Hz), 7.35 (1H, d, J=10 Hz).

EXAMPLE 4

Production of the aniline (II: X=Cl; R=iso--C₃ H₇):

A suspension of 4-chloro-2-fluoro-5-isopropoxynitrobenzene (13.5 g) andplatinum dioxide (0.4 g) in ethanol (300 ml) was subjected to catalyticreduction with hydrogen under room temperature and atmospheric pressure,whereby a designed amount of hydrogen was absorbed. The resultantmixture was filtered to remove insoluble materials, and the filtrate wasconcentrated. The residue was subjected to purification by silica gelchromatography to obtain 5.6 g of4-chloro-2-fluoro-5-isopropoxyphenylaniline. n_(D) ²⁴.5 1.5360.

NMR (CDCl₃) δ(ppm): 1.3 (6H, d, J=6 Hz), 3.7 (2H, m, J=1.5 Hz), 4.35(1H, q, J=6 Hz), 6.45 (1H, d, J=7 Hz), 7.1 (1H, d, J=10 Hz).

IR ν_(max) (cm⁻¹): 3450, 3550.

In the same manner as above, there can be produced4-bromo-2-fluoro-5-isopropoxyphenylaniline. n_(D) ²⁵.0 1.5547.

EXAMPLE 5

Production of the hydroxyphenyltetrahydrophthalimide (III: X=Cl):

2-Chloro-4-fluoro-5-aminophenol (6.6 g) and 3,4,5,6-tetrahydrophthalicanhydride (6 g) were dissolved in acetic acid (20 ml) and refluxed for 2hours. The resultant mixture was allowed to cool to room temperature andpoured into ice-water, followed by extraction with ether. The etherextract was washed with a saturated sodium hydrogen carbonate solutionand water in this order, dried over anhydrous magnesium sulfate andconcentrated. The residue was purified by silica gel chromatography toobtain 4.0 g ofN-(4-chloro-2-fluoro-5-hydroxyphenyl)-3,4,5,6-tetrahydrophthalimide.M.P., 151° C.

NMR (CDCl₃, D₆ -DMSO) δ(ppm): 1.5-2.0 (4H, m), 2.1-2.6 (4H, m), 6.8 (1H,d, J=6 Hz), 7.15 (1H, d, J=10 Hz).

IR ν_(max) ^(nujol) (cm⁻¹): 3380, 1680.

EXAMPLE 6

Production of the hydroxyphenyltetrahydrophthalimide (III: X=Br):

In the same manner as in Example 5 but using2-bromo-4-fluoro-5-aminophenol in place of2-chloro-4-fluoro-5-aminophenol, there was producedN-(4-bromo-2-fluoro-5-hydroxyphenyl)-3,4,5,6-tetrahydrophthalimide.M.P., 167°-168° C.

NMR (CDCl₃, D₆ -DMSO) δ(ppm): 1.5-2.0 (4H, m), 2.1-2.7 (4H, m), 6.8 (1H,d, J=6 Hz), 7.25 (1H, d, J=10 Hz).

IR ν_(max) ^(nujol) (cm⁻¹): 3380, 1690.

EXAMPLE 7

Production of the alkoxy-nitrobenzene (VI: X=Cl; R=iso--C₃ H₇):

To a solution of 2-chloro-4-fluoro-5-nitrophenol (19.1 g) inacetonitrile (100 ml), there was added anhydrous potassium carbonate (8g). After stirring at room temperature for several minutes, isopropyliodide (25 g) was added thereto, and the resultant mixture was heatedunder reflux for 3 hours. After being allowed to cool to roomtemperature, water was added thereto, and the reaction mixture wasextracted with ether. The ether extract was washed with a 5% aqueoussodium hydroxide solution and water in this order, dried over anhydrousmagnesium sulfate and subjected to filtration. The filtrate wasconcentrated under reduced pressure, and the residue was recrystallizedfrom ethanol to obtain 13.5 g of4-chloro-2-fluoro-5-isopropoxynitrobenzene. M.P., 61.3°-62.4° C.

NMR (CDCl₃) δ(ppm): 1.42 (6H, d, J=7 Hz), 4.3-4.8 (1H, m), 7.28 (1H, d,J=10 Hz), 7.48 (1H, d, J=6 Hz).

In the same manner as above, there can be produced4-bromo-2-fluoro-5-isopropoxynitrobenzene. M.P., 65.5°-66.5° C.

EXAMPLE 8

Production of the aminophenol (VII: X=Cl):

A suspension of 2-chloro-4-fluoro-5-nitrophenol (9.17 g) and platinumdioxide (500 mg) in ethanol (120 ml) was subjected to catalyticreduction with hydrogen under room temperature and atmospheric pressureuntil a designed amount of hydrogen was absorbed. The catalyst wasremoved by filtration, and the filtrate was concentrated. The residuewas extracted with ether, and the ether layer was concentrated to obtain6.6 g of 3-amino-6-chloro-4-fluorophenol. M.P., 145°-146° C. (decomp.).

NMR (CDCl₃, D₆ -DMSO) δ(ppm): 6.4 (1H, d, J=8 Hz), 6.85 (1H, d, J=11Hz).

IR ν_(max) ^(nujol) (cm⁻¹): 3400, 3320.

EXAMPLE 9

Production of the aminophenol (VII: X=Br):

In the same manner as above but using 2-bromo-4-fluoro-5-nitrophenol inplace of 2-chloro-4-fluoro-5-nitrophenol, there was produced3-amino-6-bromo-4-fluorophenol. M.P., 129°-130.5° C. (decomp.).

NMR (CDCl₃, D₆ -DMSO) δ(ppm): 6.57 (1H, d, J=8 Hz), 7.1 (1H, d, J=11Hz).

IR ν_(max) ^(nujol) (cm⁻¹): 3400, 3320.

EXAMPLE 10

Production of the nitrophenol (V: X=Cl):

2-Chloro-4-fluorophenol (83.4 g) was added to a solution of sodiumhydroxide (27.7 g) in water (450 ml), and methyl chloroformate (69.2 g)was dropwise added thereto at a temperature of below 10° C. Precipitatedcrystals were collected by filtration and washed with water to givemethyl (2-chloro-4-fluorophenyl)formate (134.8 g). M.P., 69°-71° C.

Methyl (2-chloro-4-fluorophenyl)formate (134.8 g) obtained above wassuspended in conc. sulfuric acid (50 ml). To the suspension, a mixtureof conc. sulfuric acid (50 ml) and conc. nitric acid (50 ml) was addedat about 30° C., and the mixture was stirred for 1 hour at thistemperature. The reaction mixture was poured into ice water, andprecipitated crystals were collected and washed with water. Methyl(2-chloro-4-fluoro-5-nitrophenyl)formate (143 g) was thus obtained.M.P., 53°-55° C.

The product obtained as above was combined with sodium hydroxide (27 g)and water (300 ml), and the resultant mixture was refluxed for 4 hours.Precipitated insoluble materials were filtered using a celite, and thefiltrate was acidified with conc. hydrochloric acid. Precipitatedcrystals were filtered and washed with water to obtain 76.3 g of2-chloro-4-fluoro-5-nitrophenol. M.P. 106°-107° C.

NMR (CDCl₃, D₆ -DMSO) δ(ppm): 7.25 (1H, d, J=10 Hz), 7.64 (1H, d, J=6Hz).

IR ν_(max) ^(nujol) (cm⁻¹): 3370.

EXAMPLE 11

Production of the nitrophenol (V: X=Br):

2-Bromo-4-fluorophenol (28 g) was added to a solution of sodiumhydroxide (7 g) in water (100 ml), and methyl chloroformate was dropwiseadded thereto at a temperature of below 10° C. Precipitated crystalswere collected by filtration and washed with water to give methyl(2-bromo-4-fluorophenyl)formate (41 g). M.P., 80.7° C.

The thus obtained methyl (2-bromo-4-fluorophenyl)formate was suspendedin conc. sulfuric acid (13 ml). To the suspension, a mixture of conc.sulfuric acid (13 ml) and conc. nitric acid (13 ml) was added at about30° C. The mixture was stirred for 30 minutes and poured onto ice.Precipitated crystals were thoroughly washed with water, whereby yellowcrystals of methyl (2-bromo-4-fluoro-5-nitrophenyl)formate (38.3 g) wereobtained. M.P., 63.5°-64.5° C.

The product thus obtained was refluxed together with sodium hydroxide(6.2 g) and water (100 ml) for 3 hours. Insoluble materials werefiltered, and the filtrate was acidified with hydrochloric acid.Precipitated crystals were collected by filtration and washed with waterto obtain 25 g of 2-bromo-4-fluoro-5-nitrophenol. M.P., 126°-127° C.

NMR (CDCl₃, D₆ -DMSO) δ(ppm): 7.42 (1H, d, J=10 Hz), 7.65 (1H, d, J=6Hz).

IR λ_(max) ^(nujol) (cm⁻¹): 3450.

In the practical usage of the tetrahydrophthalimides (I), they may beapplied as such or in any preparation form such as wettable powders,emulsifiable concentrates, granules, suspensions or dusts.

In producing such preparation a form, a solid or liquid carrier may beused. As for the solid carrier, there may be exemplified mineral powders(e.g. kaolin, bentonite, montmorillonite, talc, diatomaceous earth,mica, vermiculite, gypsum, calcium carbonate, apatite, syntheticwater-containing silicon hydroxide), vegetable powders (e.g. soybeanpowder, wheat flour, wooden powder, tobacco powder, starch, crystallinecellulose), high molecular weight compounds (e.g. petroleum resin,polyvinyl chloride, dammar gum, ketone resin), alumina, wax and thelike.

As for the liquid carrier, ther may be exemplified alcohols (e.g.methanol, ethanol, ethylene glycol, benzyl alcohol), aromatichydrocarbons (e.g. toluene, benzene, xylene, methylnaphthalene),halogenated hydrocarbons (e.g. chloroform, carbon tetrachloride,monochlorobenzene), ethers (e.g. dioxane, tetrahydrofuran), ketones(e.g. acetone, methylethylketone, cyclohexanone), esters (e.g. ethylacetate, butyl acetate, ethylene glycol acetate), acid amides (e.g.dimethylformamide), nitriles (e.g. acetonitrile), ether alcohols (e.g.ethylene glycol ethyl ether), water and the like.

A surface active agent used for emulsification, dispersion or spreadingmay be any of the non-ionic, anionic, cationic and amphoteric type ofagents. Examples of the surface active agent include polyoxyethylenealkyl ethers, polyoxyethylene alkylaryl ethers, polyoxyethylene fattyacid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fattyacid esters, oxyethyleneoxypropylene polymers, polyoxyethylene alkylphosphates, fatty acid salts, alkyl sulfates, alkyl sulfonates,alkylaryl sulfonates, alkyl phosphates, polyoxyethylene alkyl sulfate,quaternary ammonium salts, and the like. But the surface active agent isnot of course limited to these compounds. And, if necessary, gelatin,casein, sodium alginate, starch, agar, polyvinyl alcohol, ligninsulfonicacid or the like may be used as an auxiliary agent.

In the preparation of a herbicidal composition, the content of thetetrahydrophthalimide (I) may be from 1 to 95% by weight, preferablyfrom 3 to 80% by weight.

The tetrahydrophthalimide (I) of the invention may be used together withother herbicides to improve their activity as herbicides, and in somecases, a synergistic effect can be expected. Further, they may be alsoapplied in combination with insecticides, nematocides, fungicides, plantgrowth regulators or fertilizers, depending upon the need.

The dosage rate of the tetrahydrophthalimide (I) may vary on theirkinds, the sorts of cultivated plants, the modes of application, etc.Generally, however, the dosage rate is from 0.1 to 50 grams, preferablyfrom 0.5 to 30 grams, of the active ingredient per are.

Practical embodiments of the herbicidal composition according to theinvention are illustratively shown in the following examples whereinparts and % are by weight.

PREPARATION EXAMPLE 1

Eighty parts of Compound No. 1 or 2, 3 parts of alkylsulfate, 2 parts ofligninsulfonate and 15 parts of water-containing silicon hydroxide arewell mixed while being powdered to obtain a wettable powder.

PREPARATION EXAMPLE 2

Ten parts of Compound No. 1 or 2, 3 parts of alkylarylsulfate, 7 partsof polyoxyethylene alkylaryl ether, 60 parts of cyclohexanone and 20parts of xylene are well mixed while being powdered to obtain anemulsifiable concentrate.

PREPARATION EXAMPLE 3

Five parts of Compound No. 1 or 2, 1 part of water-containing siliconhydroxide, 35 parts of bentonite and 59 parts of kaolin are well mixedwhile being powdered. The mixture is then kneaded with water, granulatedand dried to obtain a granule.

PREPARATION EXAMPLE 4

Three part of Compound No. 1 or 2, 0.3 part of isopropyl phosphate, 66.7parts of kaolin and 30 parts of talc are well mixed while being powderedto obtain a dust.

PREPARATION EXAMPLE 5

Twenty parts of Compound No. 1 or 2 is mixed with 60 parts of of anaqueous solution containing 3% polyoxyethylene sorbitan monolaurate andgrained until the particle size of the active ingredient becomes lessthan 3 microns. Twenty parts of an aqueous solution containing 3% ofsodium alginate as a dispersing agent is introduced therein to obtain asuspension.

The application of the tetrahydrophthalimides (I) as herbicides will beillustratively shown in the following Examples wherein the phytotoxicityto cultivated plants and the herbicidal activity on weeds were evaluatedas follows: the aerial parts of the test plants were cut off and weighed(fresh weight); the percentage of the fresh weight of the treated plantto that of the untreated plant was calculated with the latter freshweight taken as 100; and the crop damage and the herbicidal activitywere evaluated by the standard given in the table below. The ratingvalues of phytotoxicity, 0 and 1, and those of herbicidal effect, 5 and4, are generally regarded as satisfactory to protect cultivated plantsand control weeds, respectively. The rating values in the paddy fieldtest alone were calculated from the dry weight of the test plants.

    ______________________________________                                                      Fresh weight                                                                  (percentage to                                                  Rating        untreated plot) (%)                                             value         Crop plant                                                                              Weeds                                                 ______________________________________                                        5              0-39     0                                                     4             40-59      1-10                                                 3             60-79     11-20                                                 2             80-89     21-40                                                 1             90-99     41-60                                                 0             100        61-100                                               ______________________________________                                    

The following control compounds were used in the Examples:

    ______________________________________                                        Com-                                                                          pound                                                                         No.   Structure                 Remarks                                       ______________________________________                                               ##STR9##                 U.S. Pat. No. 4,032,326                       B                                                                                    ##STR10##                U.K. Patent Publn. No. 2046754A               C                                                                                    ##STR11##                Atrazine                                      ______________________________________                                    

TEST EXAMPLE 1

Plastic trays (35 cm×25 cm×10 cm) were filled with upland field soil,and the seeds of corn, velvetleaf, sunflower, sicklepod, tallmorningglory, wild mustard and common chickweed were separately sowed inthe trays and grown for 2 weeks in the greenhouse. Each of two trays wasset in a frame (50 cm×100 cm×40 cm) and a designed amount of the testcompound was sprayed to the foliage of the test plants over the top bymeans of a small hand sprayer. After the spraying, the test plants werefurther grown for 3 weeks in the greenhouse, and herbicidal activity andphytotoxicity were examined. The results are shown in Table 1. In thisfoliar treatment, the test compounds were formulated into anemulsifiable concentrate according to Preparation Example 2 and appliedby dispersing it in 25 ml of water with the addition of a spreadingagent. At the time of application, the test plants were in a 1 to 3-leafstage and 2 to 20 cm in height.

                                      TABLE 1                                     __________________________________________________________________________    Dosage                                                                        (weight of                                                                    active in-  Phyto-                                                                            Herbicidal activity                                           Compound                                                                            gredient,                                                                           toxicity                                                                          Velvet-                                                                            Sun-                                                                              Sickle-                                                                           Tall morning-                                                                        Wild Common                               No.   g/are)                                                                              Corn                                                                              leaf flower                                                                            pod glory  mustard                                                                            chickweed                            __________________________________________________________________________    1     2.5   1   5    5   5   5      5    5                                          1.25  1   5    5   5   5      5    4                                          0.63  0   5    5   4   5      4    3                                    2     2.5   1   5    5   5   5      5    5                                          1.25  1   5    5   5   5      5    4                                          0.63  0   5    4   3   5      4    3                                    A     10    3   5    5   4   5      5    2                                          5     3   5    5   4   5      4    1                                          2.5   2   5    4   3   4      3    1                                          1.25  1   3    2   1   3      2    0                                    B     10    3   5    5   4   5      5    3                                          5     2   5    5   3   4      4    2                                          2.5   2   4    4   2   4      3    1                                          1.25  0   2    3   0   2      1    0                                    C     10    0   5    5   2   5      5    5                                          5     0   3    5   0   4      5    5                                    __________________________________________________________________________

TEST EXAMPLE 2

Seeds of corn and broad-leaved weeds such as cocklebur, common purslaneand tall morningglory were sowed in the field as previously laid up inridges, each ridge having an upper width of 1 m. At the time when thecorn grew up to the 6-leaf stage and the broad-leaved weeds up to 2 to5-leaf stages, a designed amount of the test compound formulated into anemulsifiable concentrate according to Preparation Example 2 anddispersed in water was sprayed to the foliage of the test plants withthree replications over the top by means of a small hand sprayer at aspray volume of 5 liters per are. After cultivation for 3 weeks,herbicidal activity and phytotoxicity were examined. The results areshown in Table 2.

                  TABLE 2                                                         ______________________________________                                        Dosage                                                                        (weight of                                                                    active in-    Phyto-  Herbicidal activity                                     Compound                                                                              gredient, toxicity                                                                              Cock-                                                                              Common Tall morning-                           No.     g/are)    Corn    lebur                                                                              purslane                                                                             glory                                   ______________________________________                                        1       0.63      1       5    5      5                                               0.32      1       5    5      4                                               0.16      0       5    5      3                                       A       1.25      1       4    3      2                                               0.63      0       1    2      2                                       B       1.25      1       4    4      4                                               0.63      1       2    3      3                                       ______________________________________                                    

TEST EXAMPLE 3

Seeds of corn, tall morningglory, velvetleaf, jimsonweed, commonragweed, ladysthumb, redroot pigweed and green foxtail were sowed in thefield as previously laid up in ridges, each ridge having an upper widthof 1 m.

Thereafter, the ridges were plotted in 3 m² and a designed amount of thetest compound formulated into an emulsifiable concentrate according toPreparation Example 2 was dispersed in water and applied by spraying tothe plots with three replications over the top by means of a small handsprayer at a spray volume of 5 liters per are. After cultivation for 5weeks, herbicidal activity and phytotoxicity were examined. The resultsare shown in Table 3.

                                      TABLE 3                                     __________________________________________________________________________    Dosage                                                                        (weight of                                                                    active in-  Phyto-                                                                             Herbicidal activity                                          Compound                                                                            gredient,                                                                           toxicity                                                                           Cock-                                                                            Tall morning-                                                                        Velvet-                                                                            Jimson-                                                                            Common                                                                             Ladys-                                                                            Redroot                                                                            Green                      No.   g/are)                                                                              Corn lebur                                                                            glory  leaf weed ragweed                                                                            thumb                                                                             pigweed                                                                            foxtail                    __________________________________________________________________________    1     8     0    5  5      5    5    5    5   5    5                                4     0    4  5      5    5    5    5   5    4                          C     20    0    0  3      2    5    4    5   5    0                                10    0    0  2      1    3    2    4   3    0                          __________________________________________________________________________

TEST EXAMPLE 4

Wagner's pots (1/5000 are) were filled with paddy field soil containingthe seeds of broad-leaved weeds (e.g. monochoria, false pimpernel,toothcup) and the seeds of barnyardgrass and hardstem bulrush, and waterwas poured therein until the depth of water becomes 4 cm. Rice seedlingsof the 3.5-leaf stage and the tubers of arrowhead were transplantedtherein and grown for 2 days in a greenhouse. A designed amount of thetest compound formulated in an emulsifiable concentrate according toPreparation Example 2 was applied to the pots by perfusion. Thereafter,the test plants were grown for an additional 3 weeks in the greenhouse,and herbicidal activity and phytotoxicity were examined. The results areshown in Table 4. In this treatment, the emulsifiable concentrate wasdispersed in water for application at a perfusion volume of 10 litersper are.

                                      TABLE 4                                     __________________________________________________________________________    Dosage                                                                        (weight of  Phyto-                                                            active in-  toxicity                                                                          Herbicidal activity                                           Compound                                                                            gredient,                                                                           Rice                                                                              Barnyard-                                                                           Broad-leaved                                                                         Hardstem                                                                           Arrow-                                      No.   g/are)                                                                              plant                                                                             grass weed   bulrush                                                                            head                                        __________________________________________________________________________    1     2.5   1   5     5      5    5                                                 1.25  0   5     5      4    4                                           2     2.5   1   5     5      5    5                                                 1.25  0   4     5      4    4                                           A     2.5   1   2     5      3    0                                                 1.25  0   1     5      2    0                                           B     2.5   0   3     5      2    0                                                 1.25  0   1     5      1    0                                           __________________________________________________________________________

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention.

What is claimed is:
 1. A compound of the formula: ##STR12## wherein X isa chlorine atom or a bromine atom.
 2. A herbicidal composition whichcomprises the compound according to claim 1 as an active ingredient andan inert carrier.
 3. A method for controlling weeds which comprisesapplying as an active ingredient a herbicidally effective amount of thecompound of the formula: ##STR13## wherein X is a chlorine atom or abromine atom.